FIG. 3.

Correspondence analysis biplots of bacterial community compositions in Lake Mendota. Seasonal dynamics of bacterioplankton communities were assessed from April 2002 to October 2004 using ARISA relative fluorescence values. ARISA data were generated with two different primer sets: (A) 1406f/23Sr (6) and (B) ITSF/ITSReub (3). Squares, samples collected in spring and fall; circles, samples collected in summer. Vectors represent environmental variables; the direction of increase for each variable and the length of each arrow indicate the degree of correlation with the ordination axes. TP, total phosphorus; TEMP, water temperature; DRP, dissolved reactive phosphorus; NH4, ammonium; NO2NO3, nitrite and nitrate.